This invention relates to a method and apparatus for preparing animal feedstuff and particularly to a method and apparatus which can prepare a flowable animal feedstuff from cotton seed.
Fluffy cotton seed is the cotton seed including a quantity of adherent cotton fibres, and is the product left over after the main cotton ball has been removed by ginning. Fluffy cotton seed is produced in large amounts and is generally considered to be a waste product. However, because of its high nutrient quantity, it has been considered for use as an animal feed supplement and in this context has been used by dairy farms.
A disadvantage with fluffy cotton seed is its inability to form a flowable product. Thus, it is found that the fluffy cotton seed has a tendency to tangle and form clumps of large sizes resulting in extreme difficulties in bulk handling of the product.
The present invention has developed a method and apparatus where fluffy cotton seed can be treated to form a flowable product which has good bulk handling properties.
In one form, the invention resides in a method for preparing a flowable animal feedstuff comprising cotton seed, the method comprising
subjecting fluffy cotton seed to a delinting step to at least partially remove lint and/or tails from the cotton seed; PA1 at least partially coating the delinted cotton seed with a binder; PA1 at least partially coating the delinted cotton seed with a filler; and PA1 drying the coated cotton seed to produce a flowable product. PA1 a delinter to at least partially remove lint and/or tails from the cotton seed; PA1 first coating means to at least partially coat the delinted cotton seed with a binder; PA1 second coating means to at least partially coat the delinted cotton seed with a filler; PA1 a drier to dry the coated cotton seed to produce a flowable product; and PA1 conveying means to convey the cotton seed between the delinter, first coating means, second coating means and drier.
Suitably, the binder is added to the delinted cotton seed before the filler, although combined addition of the binder and filler together is envisaged.
Suitably, the fluffy cotton seed is delinted by a heating step, which may include contacting the fluffy cotton seed with a flame. Alternatively, chemical delinting or delinting using cryogenic techniques are envisaged.
The delinting step suitably includes a combination of heating the fluffy cotton seed to at least partially burn, singe or carbonised the fluffy parts of the cotton seed, and separating the burnt, singed or carbonised parts by a separating action such as an abrasion step. The abrasion step may be achieved by vibrating or tumbling the cotton seed to remove the burnt fluffy parts.
In another form, the invention resides in an apparatus for preparing a flowable animal feedstuff comprising cotton seed, the apparatus comprising
The apparatus may further include a hopper for storing fluffy cotton seed to be passed to the delinter.
Suitably, the hopper outlet is associated with a first conveying means to convey the hopper contents towards the delinter.
The first conveying means may comprise an endless belt conveyor having an upper surface which passes beneath the hopper outlet. Suitably, the upper surface is spaced just below the outlet to also function as a closure for the outlet when the conveyor is not in use. A screw conveyor may also be used.
The first conveying means may have a discharge end to pass the cotton seed to the delinter. Suitably, the discharge end initially passes the cotton seed into a feeding means to feed the cotton seed to the delinter. The feeding means may comprise a rotary feeder.
The delinter may comprise a heating means to at least partially burn or singe or carbonise fluffy parts of the cotton seed. This may comprise the lint and/or tails of the cotton seed.
The heating means may comprise one or more flame emitters or burners. Suitably, the cotton seed is conveyed past the flame emitters along a second conveying means. The second conveying means may comprise a vibrating bed which may be inclined to facilitate movement of the cotton seed from an upper inlet end to a lower outlet end of the vibrating bed.
The vibrating bed may be provided with a plurality of apertures to facilitate removal of the burnt, singed or carbonised lint and/or tails of the cotton seed. Suitably, a collection bed or container is provided beneath the vibrating bed to collect any such material which passes through the apertures.
The delinting operation may be such as to remove about 50% of the cotton. This may result in reduction of the total weight of the fluffy cotton seed by about 5%.
In an alternative, the cotton seed may pass through a rotary trommel provided with a plurality of apertures. The rotary trommel may also function to remove the burnt, singed or carbonised products which may pass through the apertures and to a collecting bed or tray. The heating means may be present in or before the trommel.
Rotation of the trommel or vibrating of the vibrating bed may cause a buffing or abrasion action to facilitate removal of the burnt portions of the cotton seed.
In a further embodiment, the delinter may comprise a rotating trommel fitted with a plurality of burners in a plurality of chambers. These chambers can be operated separately to adjust for the amount of lint on the white seed coming from various ginning companies. The heat from this type of delinter can be harvested to assist the drying process. Part of this rotating trommel can consist of a screening section to remove carbonised lint and impurities in the cotton seed such as sticks and leaf material.
The first coating means may at least partially coat the cotton seed with a binder. The first coating means may comprise a spray coater or nozzle which may spray or pass the binder onto the cotton seed.
The first coating means is suitably located such that cotton seed passing from the delinter is passed towards the first coating means.
The delinted cotton seed may prevent or reduce the possibility of agglomeration between cotton seeds having long cotton fibrils during the coating process.
The main function of the binder is to cement the adherent cotton fibres to the seed and to act as a base to which the filler can be adhered to so as to substantially encapsulate the seed and provide a flowable product.
Therefore, the binder may be such that at its use temperature (usually ambient) it initially has a sticky or tacky consistency but is capable of changing to a non-sticky or tacky state when mixed with the filler and/or dried or heated.
The binder may include gums, such as gum arabic, starches, lignasite (a tree sap residue produced as a byproduct in paper making), a molasses or molasses-containing product, or a syrup such as corn syrup. The molasses may include the molasses left after crystallisation of sugar therefrom or a dundar. A mixture of binders may be used.
The binder may be diluted if necessary or required, to make it more flowable and therefore improve its spray characteristics. A suitable diluting agent is water. When molasses is used, it is preferred to use a one-to-one ratio of molasses and water.
An advantage of utilising water is that spray coating step may also facilitate extinguishing any still burning or smouldering cotton seed which has been conveyed past the delinter.
The coated cotton seed may be further coated by a second coating means where one or more fillers can be added to the cotton seed. The second coating means may comprise a continuous flow coater.
The filler may be provided to make the feedstuff flowable. A secondary purpose may be as a nutrient provider. Suitable fillers are inert mineral powders such as calcium carbonate, lime, diatomaceous earth, forms of clay such as bentonite and kaolin, extruded or textured proteins such as those derived from soybeans, and ground cereal grains such as corn, wheat, barley, maize and sorghum. Mixture of these and other fillers are also useful. The most preferred filler is bentonite, which is a colloidal clay commonly used as a food additive and which is readily available, and mixtures of bentonite with lime and diatomaceous earth.
The nature of the binder and filler will primarily be determined by the particular type of animal the feedstuff is required for and whether the feedstuff is intended only as a supplement or as a complete food.
Therefore, other additives may also be included in the coating. These may comprise vitamins, minerals, trace elements, veterinary products for the prevention, control or eradication of disease, growth stimulating factors and the like.
The drier may comprise a fluidised bed fryer which may dry the cotton seed by application of hot air. Suitably, hot air is recycled from the hearing means in the delinter and if necessary, additional heat (such as by a booster heating means) may be provided to heat the air to the required temperature.
If necessary, a cooling chamber may be located adjacent the drier to cool the heated cotton seed to a temperature where it can be handled, packaged and the like.
The outlet may be located in the cooling chamber.
The invention will be further illustrated by the following embodiment as illustrated in the accompanying drawings.